I owned a 2976 Hunter 27 in the early 80s. It had terrible weather helm, as did every other Hunter 27 that I spoke to the owners about. However I thought the rudder post was ben and got dimensions from the manufacturer. That confirmed that it was in fact bent back about 4 inches. All those other 27s? Most of them were bent worse than mine! That's Barnegat Bay, NJ.
I pulled it off and straightened it by hanging it in a hydraulic press with nylon slings and pressing on the leading edge. I got it back to factory specs, but it split along the edges where the two halves were put together so I had to retape the edges with fiberglass.
Recently I split the rudder on my Etap 26, because the aluminum rudder post was badly corroded between the hull and the rudder blade. However once splitting the rudder I found NO corrosion at all inside. The foam core which was exposed to the water for 25 years was also quite dry, much to my surprise! I concluded that the corrosion was due to the yards painting the rudder post every time it was hauled with copper bottom paint. A real no-no on an aluminum shaft!
Spliting the rudder was easy using a 4-1/2 grinder with a 1/16" thick cutting wheel for metal. It took me about an hour total. I then pried off one side that was not bonded with glass cloth to the rudder post and some bars welded to it. A few minutes with the grinder and I had the shaft out. At that point straightening it becomes easy.
On the Hunter 27 I worried about the post getting bent again, because it was quite thin. So I inserted a smaller heavy wall stainless pipe inside the tube. It fit a little loose but the tube will deflect just a little then the pipe will pick up the load. If I were to do it again I'd do what someone else suggested, pour epoxy down the inside of the pipe. It would rise up the outside and fill the gap between the pipe and tube and essentially make it one piece.
By the way, then I worried about tearing the fiberglass rudder tube right out of the hull. So I went back and glassed the whole area around the tube under the cockpit.
Gary H. Lucas